immortalwrt-mt798x/target/linux/mediatek/patches-5.4/0322-fix-dirty-race-between-do_tmpfile.patch

--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -356,6 +356,32 @@ out_budg:
 	return err;
 }
 
+/**
+ * lock_2_inodes - a wrapper for locking two UBIFS inodes.
+ * @inode1: first inode
+ * @inode2: second inode
+ *
+ * We do not implement any tricks to guarantee strict lock ordering, because
+ * VFS has already done it for us on the @i_mutex. So this is just a simple
+ * wrapper function.
+ */
+static void lock_2_inodes(struct inode *inode1, struct inode *inode2)
+{
+	mutex_lock_nested(&ubifs_inode(inode1)->ui_mutex, WB_MUTEX_1);
+	mutex_lock_nested(&ubifs_inode(inode2)->ui_mutex, WB_MUTEX_2);
+}
+
+/**
+ * unlock_2_inodes - a wrapper for unlocking two UBIFS inodes.
+ * @inode1: first inode
+ * @inode2: second inode
+ */
+static void unlock_2_inodes(struct inode *inode1, struct inode *inode2)
+{
+	mutex_unlock(&ubifs_inode(inode2)->ui_mutex);
+	mutex_unlock(&ubifs_inode(inode1)->ui_mutex);
+}
+
 static int do_tmpfile(struct inode *dir, struct dentry *dentry,
 		      umode_t mode, struct inode **whiteout)
 {
@@ -364,7 +390,7 @@ static int do_tmpfile(struct inode *dir,
 	struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
 					.dirtied_ino = 1};
 	struct ubifs_budget_req ino_req = { .dirtied_ino = 1 };
-	struct ubifs_inode *ui, *dir_ui = ubifs_inode(dir);
+	struct ubifs_inode *ui;
 	int err, instantiated = 0;
 	struct fscrypt_name nm;
 
@@ -426,11 +452,11 @@ static int do_tmpfile(struct inode *dir,
 	instantiated = 1;
 	mutex_unlock(&ui->ui_mutex);
 
-	mutex_lock(&dir_ui->ui_mutex);
+	lock_2_inodes(dir, inode);
 	err = ubifs_jnl_update(c, dir, &nm, inode, 1, 0);
 	if (err)
 		goto out_cancel;
-	mutex_unlock(&dir_ui->ui_mutex);
+	unlock_2_inodes(dir, inode);
 
 	ubifs_release_budget(c, &req);
 	fscrypt_free_filename(&nm);
@@ -438,7 +464,7 @@ static int do_tmpfile(struct inode *dir,
 	return 0;
 
 out_cancel:
-	mutex_unlock(&dir_ui->ui_mutex);
+	unlock_2_inodes(dir, inode);
 out_inode:
 	make_bad_inode(inode);
 	if (!instantiated)
@@ -673,32 +699,6 @@ static int ubifs_dir_release(struct inod
 	return 0;
 }
 
-/**
- * lock_2_inodes - a wrapper for locking two UBIFS inodes.
- * @inode1: first inode
- * @inode2: second inode
- *
- * We do not implement any tricks to guarantee strict lock ordering, because
- * VFS has already done it for us on the @i_mutex. So this is just a simple
- * wrapper function.
- */
-static void lock_2_inodes(struct inode *inode1, struct inode *inode2)
-{
-	mutex_lock_nested(&ubifs_inode(inode1)->ui_mutex, WB_MUTEX_1);
-	mutex_lock_nested(&ubifs_inode(inode2)->ui_mutex, WB_MUTEX_2);
-}
-
-/**
- * unlock_2_inodes - a wrapper for unlocking two UBIFS inodes.
- * @inode1: first inode
- * @inode2: second inode
- */
-static void unlock_2_inodes(struct inode *inode1, struct inode *inode2)
-{
-	mutex_unlock(&ubifs_inode(inode2)->ui_mutex);
-	mutex_unlock(&ubifs_inode(inode1)->ui_mutex);
-}
-
 static int ubifs_link(struct dentry *old_dentry, struct inode *dir,
 		      struct dentry *dentry)
 {